49 CFR 395.3
(a) Except as provided in §395.1(b)(1), 395.1(f), and 395.1(i), no motor carrier shall permit or require any driver used by it to drive nor shall any such driver drive:
(a)(1) More than 10 hours following 8 consecutive hours off duty; or
(a)(2) For any period after having been on duty 15 hours following 8 consecutive hours off duty.
(b) No motor carrier shall permit or require a driver of a commercial motor vehicle to drive, nor shall any driver drive, regardless of the number of motor carriers using the driver's services, for any period after --
(b)(1) Having been on duty 60 hours in any 7 consecutive days if the employing motor carrier does not operate commercial motor vehicles every day of the week; or
(b)(2) Having been on duty 70 hours in any period of 8 consecutive days if the employing motor carrier operates commercial motor vehicles every day of the week.
[57 FR 33649, July 30, 1992, as amended at 60 FR 38748, July 28, 1995].